That's awful!! I'm so sorry about your mother OP. I've lost a lot of people in my family so I'm sorry for what you're most-likely going through.

As an Irish girl, I didn't realise that was unusual, in fact it would be offensive not to drink at a funeral.

I don't usually say break up, but eh... I think you should break up with your girlfriend, OP. She really has no respect for you at all.

There was a ton of beer at my mom's wake, but she was always a "celebrate life and have a good time" kind of lady.

I don't think she can really be blamed unless you discussed the wake beforehand. I doubt she did it to intentionally wind you up or upset you. Wakes are usually seen as two things - a celebration of the person's life or a time for less formal mourning after the funeral. Depending on what kind of background and family you come from, your views on wakes may be different. Where I'm from, wakes are usually more akin to wedding receptions. Lots of them are held in pubs or bars in my family.

omg you all are way too sensitive people drink when bad stuff happens so what...and dont u mean funeral? lol

woah woah andddd your from mexico? lmao u knoe u drank that beer shush

May be the beer was for you.

mi pesame desde saltillo, y en cuanto a tu novia, se la mamó , alv con ella

Depending on where the girlfriend from and culture differences this could be a nice gesture. However, On average it isn't common. It really depends on her intent and her background.